Cool blog Gian. I haven't seen the movie yet, but really enjoyed the anime series. Yes, like you I also enjoyed and found it interesting..the whole concept of morality and moral decisions, like who to kill, will removing all criminals and 'wrong-doers' from this world equate to a better world? A lot would say yes, but lol, more of US, because those that became criminals and 'wrong-doers' WERE and in fact ARE us. They are not a totally different species.
Then we instead need to ask why they became that, why do we allow a system that means people have to become that to survive, to enjoy, to feel alive or similar? So no, a death note is not the answer to making the world and people better, because if one can become 'evil' - then we all can become 'evil'. And anyone who says they have never had 'evil' thoughts, which are the exact same as negative, judgemental, mean, harsh, harmful, abusive thoughts, they are liars! It is just that their powers of suppression were stronger than those that we now know of as criminals and 'wrong-doers' etc.